bpf: Set run context for rawtp test_run callback

syzbot reported crash when rawtp program executed through the
test_run interface calls bpf_get_attach_cookie helper or any
other helper that touches task->bpf_ctx pointer.

Setting the run context (task->bpf_ctx pointer) for test_run
callback.

Fixes: 7adfc6c9

 ("bpf: Add bpf_get_attach_cookie() BPF helper to access bpf_cookie value")
Reported-by:  <syzbot+3ab78ff125b7979e45f9@syzkaller.appspotmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Closes: https://syzkaller.appspot.com/bug?extid=3ab78ff125b7979e45f9
Link: https://lore.kernel.org/bpf/20240604150024.359247-1-jolsa@kernel.org